package com.hliushi.birdge.example01;

/**
 * @author: hliushi
 * @date: 2023/2/13 17:40
 **/
public abstract class Pen {


    protected Ruler ruler;

    public Pen(Ruler ruler) {
        this.ruler = ruler;
    }

    /**
     * 抽象方法
     */
    public abstract void draw();
}
